Process of making a red azo dye.



' STATS ERNST ULRICHS, OF ELIBERFELD, GERMANY, ASSIPGNGR T CQMPANY\VfTLliIHG DELI-IL & 00., ACTIENGESELLSCHAFT, FARBENFAIBRIKEN, OFBARMEN, GERMANY.

PROCESS OF MAKING A RED AZ O DYE.

Specification of Letters Patent Fatented (lot. 5, fiWQ-s No Drawing;Original application filed March 9, 1909,8cria1 E0. $823.41. Divided andthis application file July 12, 1909.

To all whom it may concern:

Be it known that I, ERNST ULnrcris, a subject of the King of Prussia,German Emperor, and resident of Alter Markt of Elberfeld, Province ofthe Rhine, German Empire, have invented a new and useful Process for theProduction of Red Azo Dye, of which the following is a specification.

This invention relates to a process for the production of a red azo-dyewhich is specially suited for the manufacture of. colorlakes.

The present application is divided from the application of Ernst UlrichsSerial No. 482241 filed Iviarch 9th. 1909.

When an axe-dye is produced according to the method described in theUnited States Patent No. 650757 by coupling naphthylamin-sulfo acid 2.1and beta-naphthol and then boiling the dye produced after the couplingas prescribed in the above 1neutioned patent there results the dye knownin commerce as lithol-red R. It has now been discovered that the dyebefore boiling is not identical with the dye after boiling and it wouldappear that two molecules or the dye before boiling have during theboiling process taken up one molecule of water. The unboiled dye maytherefore be assumed to be an anhydrid of the boiled dye. The presentapplicant has now discovered that this anhydrid which shall be calledbriefly F-anhydrid, when the coupling is produced at ordinarytemperatures and when no boiling takes place after the coupling of thenaphthylamin-sulfo acid and the beta-napln thol then the anhydrid Verysoon takes up Water so that in a short time the ordinary lithol-red isformed. He has also discovered that a very permanent F-anhydrid isobtained if the coupling of the sulfo-acid and beta-naphthol is effectedat a high temperature either in the. presence or absence of neutralsalts of the alkalies or ammonium salts The F-anhydrid produced in thismanner may be stored in a Serial No. 507,036.

several months Without changing into litholred. When boiled however thedye of course I takes up Water and changes into the form of litholred...

The following are some particular examples of the m thod of producingthe F-anhydrid aeec to the present invention.

Example .1: kg. of the sodium salt of naphthylainin sulii'o acid 2.1 aredissolved in 400 liters water at a temperature *of 2530 C. This solutionis then mixed with 30 kg. hydrochloric acid of 20 Baum'while stirringand then the whole is diazotized with a solution of 7 kg. sodium nitritein about 351 liters Water. The diazo acid is drawn off and washedhvithWater and thenv 'and the Whole isstirred until the coupling iscompleted.

Example II: The process is carried out exactly as in Example 1, but 40liters oi a saturated solution of common salt is added to, the Washeddiazo acid in the coupling tank after which the Warm beta-napht-holsolution is added. In this case the coupling proceeds very much moreslowly than in Example 1, but the F-anhydrid produced inthis Way evenwhen allowedlto stand for a very long time does not change over into theusual dye stuff produced from naphthvlamiu sulfo acid 2.1 andbeta-naphthol. The

coupling of naphthylamin sulfo acid 2.l with beta-naphthol may beetlected at considerably higher temperatures without disturbing theeliect. Further the quantities of Water employed may be varied WithinWide limits. 7

The F-anhydrid produced according to the present invention gives Whenboiled With Turkey-red oil or monopol soap and calcium doughy t'orm for1 or ;-;trontium salts the bluish red lake Which is identical with thatproduced by the dye lakes,

consisting in coupling diazo-naphthyl amin sulfo acid 2.1 withbeta-naphthel at e. high temperature in the presence of a neutralalkaline salt.

,In Witness whereof I have hereunto set my hand in the presence of twowitnesses.

ERNST ULRICHS. [1 8.

Witnesses j OTTO Kerrie, l WILLY KLEIN.

described in application Serial N 0. 482241 and Patent Number 911186.

I claim 1. Process for the production of a red azo dye suitable for themanufacture of color lakes consisting in coupling diazo naphthylaininsulfo acid 2.1 with, beta-naphthol at ahig'h temperature.

2. Process for the production of a red azo dye suitable for themanufacture of color-

